With the right top, the ray won't get out.
I do suggest using a lot more caution that a lot of people take. As someone who has been tagged in the past and has seen a 'calm' ray get spooked and strike, they are not nearly as perdictable as they seem. People get lulled into a false sense of security.
Just be highly aware of where the animal is when doing things like cleaning the tank. Avoid even being on the same half of the tank if possible, move slow, and just take time. If the ray is aggrivated or active, come back later.
You should be fine as long as you respect the animals for what it is.